What is the most important factor when determining a safe speed?

In Ohio what is the maximum horsepower a person younger than 12 years old may operate without both an education certificate and a supervising person aboard? A power boat is underway in fog what sound do you hear? Did submarines exist in 1800's? Who is the patron saint of selling a boat? Your water heater is boiling hot and is not turning its self off? Who loads or unloads ships? What was the advantage of the steam boat that Robert Fulton created? What rhymes with canoo? Jet ski wont start but has gas and spark? How does a boat not sink? Can submarines swim? How do you get out of a drowing car? Where is the best place to cruise in November? How do you set the idle on a 1995 Yamaha 30 hp 2 stroke? Who owns motor yacht phoenix 2? How much does a 12 foot Jon boat weigh? What is required on a federally controlled waters for boats less than 39.4 feet? You see a white buoy with an orange square and black lettering. What does this buoy tell you? What is the recommended maintenance for a inboard boat? How long can a submarine stay under the water?